1. Field of the Invention
The present invention relates to power conversion apparatuses.
2. Description of Related Art
A static-Leonard power conversion apparatus using thyristors is capable of performing a step-up/down operation based on bidirectional conversion between direct current or single-phase alternating current and three-phase alternating current, and of performing rapid switching between acceleration and regeneration. The static Leonard system has general technical problems, such as low power factor caused by phase control of thyristors and low efficiency caused by cyclic currents.
Japanese Unexamined Patent Application Publication No. 2005-269735 discloses a vehicle propulsion apparatus that includes wheel motors for driving respective wheels and inverters for driving the respective wheel motors. The inverters are current-type inverters. The vehicle propulsion apparatus further includes a direct-current power supply and a plurality of direct-current generating circuits that supply current from the direct-current power supply to the respective inverters.
Japanese Unexamined Patent Application Publication No. 2-206385 discloses a technique related to controlling a duty factor of an inverter that supplies alternating-current power to an electric motor. Specifically, what is disclosed is a current-type inverter that can increase the output voltage of an inverter using a duty factor of the inverter.